SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3900df56671be6e33f0091f996612ec180dea1aee46ad365e65953c4b273b468' 
  AND token = 'JJQZaA//JGHHXujYsWJojH72ndbPrgCXl28Yz1JhpDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}