SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bacfe64c36d7a308e5c26cee81e13ed4b45d0758fb2c43dd2120861bcd29a66' 
  AND token = 'A9ZSBypTvcQUTD2Kp7CKp+QgTF8h/pDM+ayMbSgCDo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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