SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '258cbd1938469d14402b71fc2d24514e21e4eb4e89a3402efd16254da36e2969' 
  AND token = 'dHHw41FOaw8FPMizorfSnkMNrmO3E2MvxdN+JjAP4i0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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