SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7e83d050d55ed397d1890dd1517c854a9bdcdc0615ee26db6e9835d5c545ecd' 
  AND token = '5ucwVEOecHUuAG/qar8Nit6dURSSv9cE3U7UDrACfHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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