SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8de88e51c31566706c29b7a02afa53af64d34fde8f6bd3cf627a31bd55d7edd' 
  AND token = '/e94dJV0HtLtKF8hxGOMz/Zd3I+OuZCptVIPwOoPk5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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