SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf5425940a4058af928bb8ca347a433c7d8e7d4b9707ae476a941db197b31be9' 
  AND token = 'xrwK7sUlz8LjR+OtJ6zFsdmmQoxbFRJmWwujVLZpF2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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