SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cffe5e1730801226229c34b239421acd1683feb727b02f12a85a065d9bf44a0' 
  AND token = 'poP1TZvzEzXz93RU7lbKxJ48ZCkUH0Wx4knGS0xbaVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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