SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '144ba41c12e6eacbdac816276970e2df78e3fd6b6c0ce31f011810c574008e94' 
  AND token = '6XS1reL4CWO9z0TG8Foi1UNLVYbHtcPbee2cAhubRwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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