SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdf4cb8915e865550c4c807849e52cef9edbde003534ff4fb5a14663e61ee57b' 
  AND token = 'TiVGOSUbwSrFsJQwqcU+3nhzzFGccgh9KBiIbwmJOzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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