SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '792e2d4de437f57d96680192746ea34a82224899de6551bb6d136b884e80a833' 
  AND token = 'YeNlT3hAGni0J6UtpqKCuibr7noLlHyB9jThdvlbO/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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