SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4db8959b2f255bfd97b04968dc11684aaf3601952fb46470f2704119651e8814' 
  AND token = 'UbARjvlVUbx+03kUXYB1MeRkUuNRn6lJfIdANG6dv80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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