SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7419855f5cc9984197cb582d4a5d568224c61356d99716dff179e9b6454ffb66' 
  AND token = 'jK+0XdY7tm/RBh2qLuS/4Xh5l/BVKNlIBo0SJqnMaVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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