SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf74cf09a3fb8d7fc72d5274b7e858ce579b4b514f9d6793285b273ace6de24' 
  AND token = 'jH+8ezILeViMS1+kuG88kagx8cnbqEnNqEd0nKvW+zA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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