SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26f250d32addfaf04857ce9e99bdf9a92a753a99a51d9ddf3b146be3dd319da7' 
  AND token = 'KBiUyQ4UWHazlkbpDdhG6DVwD7mY3ZFWI2aTGpOLsy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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