SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15139ac894672da0882751d53f4f3177835eed51b395f0e82baae63852602696' 
  AND token = 'hkjg35iMQ9oe/nRFNAhBATu+sjg6SISS043yK2/0S6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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