SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7623b13e0c35c9fec09737d348eb4218262a30bb27f48a5c8479162b4a1c2bd' 
  AND token = 'biV73wWrffrMR/26LCJNcjrRMvyoQ+BA4skZjGBU2zY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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