SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '605d55aba819df0313c76472ebbb6a32534b5d22a9a246f80a13ae6d0e9b771d' 
  AND token = 'dy7ADKH5fBALqafjvo4wm6AS+64rWZnYJE5PiWwpB0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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