SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd610d626d7e3f741e16137364e5b9859724da18856c7cee9521a46b98f649919' 
  AND token = '93JKqJ6ifHlrkRnvZHN8qvJCGkWY1DNU9O8xjKMILgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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