The OED supplies the most likely meaning of candlelight in the context of this song: "The time during, or at, which candles are lighted; dusk, nightfall". That is, because nightfall necessitated the lighting of candles in the early modern period, night-time and candlelight became synonyms. The earliest OED citation is from the seventeenth-century - Pepys, specifically: "She and I, it being candle-light, bought meat for tomorrow".

One can easily find similar references to lighting candles at night in the sixteenth-century. In Act 2 Scene 1 of Henry IV Part 1, written in the 1590s, a group of couriers discuss their movements for the night. The scene occurs at two in the morning and one courier, asked how long it will take him to get to London, replies: "Time enough to go to bed with a candle, I warrant thee". That is, he will be able to get to London before dawn.

This meaning is most consistent with the other lyrics in the song you quote. The person asks whether one can traverse the distance before night. "Yes", if you move quickly and agilely. In fact, you could do the return journey in that time.

Whilst this is sufficient to answer your question, it might be interesting to note some connotations that candles might have in early modern England. Readers would have inherited a religious connotation from the King James Bible. Matthew says that candles were important because they share their light with others: "Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house". And there are numerous examples of candles being used to share God's light with the congregation - most famously, Moses must craft a tabernacle candlestick, which is later mandated for his brother Aaron too.

The candlestick, by its association with light, became a symbol for virtue. Thomas Nashe, for example, dedicates his pamphlet on night terrors "[t]o the new-kindled clear lamp of virginity, and the excellent adored high wonder of sharp wit and sweet beauty, Mistress Elizabeth Carey".

Sometimes this holy light revealed sins. In The Merchant of Venice, Jessica, the daughter of the Jew Shylock, is sneaking out of her family home to reunite with her new-found Christian lover. Dressed as a boy, she worries that the candlelight necessary for her night-time escape will illuminate her misdeeds - both those of cross-dressing, and the event that demands it, which is her pre-marital sexual relationship: "What, must I hold a candle to my shames? / They in themselves, good-sooth, are too too light". Here she puns on the word 'light': in seventeenth-century usage, it meant promiscuous as well as bright.

In other instances, candlelight is insufficient to combat the sins that occur at night. In the aforementioned scene from Henry IV Part 1, there is an attempted robbery by candlelight. In Middleton's The Roaring Girl, 'candlelight' suggests the half-light of the alehouse and, by extension, the sordid underworld in which sexual abuse can occur without detection:

MOLL: You remember, slave, how you abused me t'other night in a tavern?  
FELLOW: Not I, by this light.  
MOLL: No, but by candlelight you did: you have tricks to save your oaths, 
reservations have you, and I have reserved somewhat for you.
[She strikes him.]