SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4c29aa603cc2e94989c2aa0aa9201bee79eff79bb4f2a294e1028cb90277d985' 
  AND token = '6Qq+IY7xkpQsoYRsPsNxYVljUDM6xevPPisxxwrxG4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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