SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4faf163591744ea146ed835247c913f43be2c96bccd7f14aa6e7bf0da19a8d6' 
  AND token = '6e9Sb+ve3xB5hMgyg/wwAHHVqzVzfVC7f8zumcjsT8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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