SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '088214b308189845159091770efd08008e010292c1f9391942562a9f366ffd67' 
  AND token = 'yFpyQQ2okNmOJUloWktjOoJTnpCBtvCV7EJGjyH2VU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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