SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0de8f3785ddca65504e802072f72344945509e436eb665f0cc9763cc28286401' 
  AND token = 'dChhpRfqeLkXZIQ/f98YuGU8FRidVTWI12NYFjAUc54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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