SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03289a7c85bf7292aa6d489a4ed0176689f23e55459367cd2c65d3524b006d63' 
  AND token = 'CbJRnE2Rm6tBDYngEaknxVh6yqIducrUy559kkvgges=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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