SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d8e693c45a228f6785ab54288d5276ec7f53301fe9ba711db9e457354b4bc91' 
  AND token = 'dqllIgsngGdXvstUcTszjwO18lCDvEbRn1yATLpscto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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