SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc947a84bfb18284bf142ce99aae6823db72f694aa77834df0099bff923a44fb' 
  AND token = 'qxLSJUkQY6rSZUJSzB1Hwh4JXx01t0BtzFryh+j8xEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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