SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d485338e6ead709a7a57ed036504b2b49a55fc3c45ffd92d96000b4492436c0' 
  AND token = 'RMwZWukiYlNHqOcnMypdkmOXTjqvW71etC3pLyK1sio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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