SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd12ae138af69d3eca0e66ff08d92313772d0e5d78548bc6ce169b8f43fe22733' 
  AND token = 'RRY/n/iZfAkTqaxtQVZeDZN5FXoUaolZp4paSs5yFKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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