SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9300258ad5a70f39d0d7f58b9db849f427f30c706a4abd195d99dd425f6d031' 
  AND token = 'G40EYVijPM9oBkQJ4m/am3wTBFl8lykhvXEKoRaKveY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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