SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cc5bb03f89d4003ef403a165d4baea71e678d79100129d9acdd2b7b741745a6' 
  AND token = 'VQdz2Ty915kZKH/9qzuVzJqKbyTC8etk9UtHCiS+N04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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