SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c7e48a4fee78325afe713d914cb1a55c22b83c54e20773ac830d72b06a10c4b' 
  AND token = '1GpP/7s92s03fztzBAxJ5ftuxUxIpWxjohPlqKepc+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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