SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2801f0fc770858e82745679f7e3ec669725c0b017d0f505a090f9db7313678be' 
  AND token = 'k1rTbh6MMUD941DwzRjScFutw7IZfEYXHsMGXBBB4y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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