SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd6706e6a2c96ae8a95cdcd98e6fef80e00521ce921b2ef22a1e7666bc667f24' 
  AND token = 'vwQxvTgnbOFtp8QBuomnvQe2QwaOvn3lCIr3qL/8WeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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