SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e0f28ada79de3b22813bbe87969adbef04da9475d455be36c5b58830f526581' 
  AND token = 'vwPCSiNB6lsrecwYccGsVlBxXMturdxUYNjWTgGexYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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