SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d40064457f031f75e070662e57219a6c65476e6ac224da820edcd2d282e6ddf' 
  AND token = '2etYk/z4bRcxU1WULD20y8w1xsWOD/FV02kkp2QRuBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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