SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83aa36da20e725a5091ee1d3b4359da919b6b5d6ae7982a41438c7b68d5e2595' 
  AND token = '6uyHrFfnd9W/PUJTKGB4WTwIwE/VBZSxAp1zRqfn71Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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