SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6002f5ba76c0261961d697806dc6f5c202335528fb8ece312db2f71618c175db' 
  AND token = 'sHWVcchvgS9SADxmb2JK3AJe53pyOK5JD2oQq3ZB3GY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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