SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8feb3afdebd7a014db0df887beae1f9ee4f8796d0cdf0d98f600f89cfff65d64' 
  AND token = 'gItLyMuV5OGldlfQqpLfQF1jsVmF7IECqWKp0odbYX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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