SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b5498085c5bf28e97ebf7ccf9d1fd001b623e4178ac6b30454ff32e101aae56' 
  AND token = 'nGWMSqsFE8yjpfZaiijlEyRMrokWDv/Rqts8Eiy7pZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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