SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce04c5a8775e5f141a3808d08565a3616ce438e0762d6cc9c316fd843c57bc16' 
  AND token = '2+ulqZNX+P9I4xcbGrzx+sIgWZPbMCHmy7/FsO5nAJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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