SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9400ce1d1e7eedde0d154d0cdc9defcf7fe3c86e8261101982b425199fa145c5' 
  AND token = 'ByNLrZIZSeYCSJKluVEBrb9Ra9UJPwoWRSNVYp9PkSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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