SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '522efb559851986937a2a38cd927856cd3bff3ef39bb7e793294074d8f2321ae' 
  AND token = 'KgZ1hO58Aj9iCGBnDfQIWpZCS1z7N4gPPYlogNUi8IA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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