The phrase 'How long' as a question occurs both in the LXX and NT. There are some variations between ἕως τίνος and ἕως πότε (both phrases with the interrogative. The question is followed by the present or future indicative or subjunctive. The concept 'how long until' seems rarely expressed using ἕως μέχρι (3χ).
Pseudo-Zonaras Lexicogr.,
Lexicon Alphabetic letter epsilon, page 684, line 16·
σοφιστὴς Βυζάντιος, ὃς χρονικὴν
ἐπιτομὴν ἔγραψεν ἀπὸ Ἀδὰμ ἕως μέχρι τῶν
χρόνων Θεοδοσίου τοῦ μεγάλου ἐν βιβλίοις δέκα.
Here are a few citations:
Ex 10.3 εἰσῆλθεν δὲ Μωυσῆς καὶ Ααρων ἐναντίον Φαραω καὶ εἶπαν αὐτῷ Τάδε λέγει κύριος ὁ θεὸς τῶν Εβραίων
Ἕως τίνος οὐ βούλει ἐντραπῆναί με; ἐξαπόστειλον τὸν λαόν μου, ἵνα λατρεύσωσίν μοι.
Ex 16.28 28 εἶπεν δὲ κύριος πρὸς Μωυσῆν
Ἕως τίνος οὐ βούλεσθε εἰσακούειν τὰς ἐντολάς μου καὶ τὸν νόμον μου;
Nu 14.11 καὶ εἶπεν κύριος πρὸς Μωυσῆν
Ἕως τίνος παροξύνει με ὁ λαὸς οὗτος καὶ ἕως τίνος οὐ πιστεύουσίν μοι ἐν πᾶσιν τοῖς σημείοις, οἷς ἐποίησα ἐν αὐτοῖς;
Joshua 18.3 καὶ εἶπεν Ἰησοῦς τοῖς υἱοῖς Ισραηλ Ἕως τίνος ἐκλυθήσεσθε κληρονομῆσαι τὴν γῆν, ἣν ἔδωκεν κύριος ὁ θεὸς ἡμῶν;
1 Kgdoms (Samuel) 1.14 καὶ εἶπεν αὐτῇ τὸ παιδάριον Ηλι
Ἕως πότε μεθυσθήσῃ; περιελοῦ τὸν οἶνόν σου καὶ πορεύου ἐκ προσώπου κυρίου.
2 Kgdoms (Samuel) 2.26 καὶ ἐκάλεσεν Αβεννηρ Ιωαβ καὶ εἶπεν Μὴ εἰς νῖκος καταφάγεται ἡ ῥομφαία; ἦ οὐκ οἶδας ὅτι πικρὰ ἔσται εἰς τὰ ἔσχατα; καὶ
ἕως πότε οὐ μὴ εἴπῃς τῷ λαῷ ἀναστρέφειν ἀπὸ ὄπισθεν τῶν ἀδελφῶν ἡμῶν;
Ps 89.46 (LXX 88.47) 47 ἕως πότε, κύριε, ἀποστρέψεις εἰς τέλος, ἐκκαυθήσεται ὡς πῦρ ἡ ὀργή σου;
Hab 1.2 2 Ἕως τίνος, κύριε, κεκράξομαι καὶ οὐ μὴ εἰσακούσῃς;
Septuaginta: With morphology. 1996 (Hab 1:2). Stuttgart: Deutsche Bibelgesellschaft. (See also 1 reigns 16.1; Jer 31.22; Zech 1.12; Ps 13.2; Ps 35.17; Ps 79.5; Ps 80.4)
Rev 6.10 καὶ ἔκραξαν φωνῇ μεγάλῃ λέγοντες·
ἕως πότε, ὁ δεσπότης ὁ ἅγιος καὶ ἀληθινός, οὐ κρίνεις καὶ ἐκδικεῖς τὸ αἷμα ἡμῶν ἐκ τῶν κατοικούντων ἐπὶ τῆς γῆς;
Aland, B., Aland, K., Black, M., Martini, C. M., Metzger, B. M., & Wikgren, A. (1993). The Greek New Testament (4th ed.) (644). Federal Republic of Germany: United Bible Societies.
Some other structures (taken from LSJ)
εἰς πότε.....II. OF TIME,
1. to denote a certain point or limit of time, up to, until, “ἐς ἠῶ” Od.11.375; ἐς ἠέλιον καταδύντα till sunset, 9.161 (but also, towards or near sunset, 3.138); “ἐκ νεότητος ἐς γῆρας” Il.14.86; “ἐκ παιδὸς ἐς γῆρας” Aeschin.1.180; ἐς ἐμέ up to my time, Hdt.1.92, al.: with Advbs., εἰς ὅτε (cf. ἔς τε) against the time when . . , Od.2.99; εἰς πότε; until when ? how long ? S.Aj.1185 (lyr., cf. “εἰσόκἐ; εἰς ὁπότε” Aeschin.3.99; ἐς τί; = εἰς πότε; Il.5.465; ἐς ὅ until, Hdt.1.93, etc.; “ἐς οὗ” Id.1.67, 3.31, etc.; “ἐς τόδε” Id.7.29, etc.
ἕως 6 with Advbs. of Time and Place, ἕ. ὅτε till the time when, c. ind., v.l. for ἔστε in X.Cyr.5.1.25; ἕ. οὗ, f.l. for ἐς οὗ, Hdt.2.143: freq. in later Gr., Gem.l.c., Ev.Matt.1.25, etc.; ἕ. ὅτου ib.5.25, etc.; ἕ. πότε; how long? ib.17.17, Ev.Jo.10.24; ἕ. τότε LXX Ne.2.16; ἕ. ὀψέ till late, f.l.for ἐς ὀψέ, Th.3.108; ἕ. ἄρτι 1 Ep.Jo.2.9; ἕ. ὧδε as far as this place, Ev.Luc.23.5.
4. καί (page 857)
μέχρι (page 1123) 2 of Time, τέο μέχρις; i.e. τίνος μέχρι χρόνου; how long? Il.24.128; μέχρις τεῦ; Callin.1.1: in Prose, μέχρι τούτου Hdt.1.4; μέχρι οὗ, μέχρι ὅσου, Pl.Mx.245a, Hdt.8.3, al.; μ. τοσούτου, ἕως ἂν . . Th.1.90; μ. τούτου, . . μέχρις ἂν ῥηθῶσιν Din.1.91, cf. Pl.Phd.81d: with the Art., τὸ μ. ἐμεῦ up to my time, Hdt.3.10, 5.115; μ. τῆς ἐκείνου ζόης till the end of his life, Id.3.160; μ. ἡμερέων ἑπτά Id.6.12; μέχρι Πυθίων Th.5.1; μέχρι ἡλίου δύντος IG12.188.4.
6. ὅσος (page 1261) ib.5000 (Gortyn): Relat. and indirect interrog. Adj.:—of Size, as great as, how great; of Quantity, as much as, how much; of Space, as far as, how far; of Time, as long as, how long; of Number, as many as, how many; of Sound, as loud as, how loud: correl. with τόσος (τόσσος), τοσόσδε, τοσοῦτος, in sense as,
παρατείνω (page 1327) Luc. Macr.3. . as aux. Verb, c. part., ποῖ παρατενεῖς δεδιὼς ταῦτα; how long will you go on fearing this? Philostr. VA7.22, cf. 5.26. [note: ποῖ has fallen out of Koine for the most part and been replaced by ποῦ. Or is this a shortened ποῖος?]
ποῖ (page 1427) ἃ δ' ὑπέσχεο π. καταθήσεις; S.OC227 (anap.). how long? ποῖ χρῆν ἀναμεῖναι; Ar.Lys.526.
πόσος (page 1453) 3. of Time, how long? π. τινὰ χρόνον; S.OT558, etc.; π. χρόνου;πότε; Ar.Ach.83. 4 of Value, how much? πόσον δίδως; Id.Pax 1262; πόσου; at what price? Id.Ach.812,898, Pl.Ap.20b, etc.; ἐπὶ πόσῳ; ib.41a, X.Cyr.3.1.43; ἐκ πόσου is f.l. for ὁπόσου in D.50.30.
τίς ] etc.:—ἐκ τίνος; from what cause? X.An.5.8.4:—ἐς τί; to what point? how long? Il.5.465; but also, to what end? S.Tr.403, cf.
χρόνος (page 2008) ποίου χρόνου; A.Ag.278; πόσου χ.; after how long? Ar.Ach.83. dat., χρόνῳ in process of time,