SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fd830461de5390c99679e9c6c768032c82452f56553700b60c4b7373ab4ca51' 
  AND token = 'LeQRe+/rp1xT4oMOyg8FbzLm3gySMDD7ZqItNNoUOrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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