SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8df99055597a2129dc955098a351daba335a8346f88b0f2eb8efb155a2ec9776' 
  AND token = '18Gn/bhtkpQ08xJvxeAAHQERZ2/2jDKIL14n2iux4rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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