SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1b627ff7ee51c2dac7ad1361afd267098c394875722947b66fe9eda49968e24' 
  AND token = '2MrxkbdIm97wTua2MM/e7QtGpSalvFros93lnb2BuLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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