SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce5bdb0bd03a773b1d8dd714154789c89a6a38b901228f548575b991fa618ed0' 
  AND token = 'Z+PNUoqtPFDAVzRgsTlIA5bKY0TMcW6Z392CbD6uPZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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