SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78cec1218d4dcdcc86d90558fb9a450abe06107d9b61cc84487ec58c517f2cc5' 
  AND token = 'WfzjcZOIaGvzqOS0iiDd7hLVhJoDyaVg9xxDslohoO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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