SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acda7b9e67b6543f44bc278fe809c40aa032c56f02f06dda81c9ed6d871a35b3' 
  AND token = 'tCnVUTYqYy2k88tCHsHzGkCsc9EsUEDTnRGqxp+B8Ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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