SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da28f705876913cb4dba8009aa216ebc6adff8cf6631e136277d58ad7e306c4b' 
  AND token = 'p+uDVFs1K/hlwaaonWN0iq8xDGJdbBzIJyyUNlzRL8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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