SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6fc7280db0378755d80f3fbc90968762544d6f4f82b20784bce4f95a36baca2' 
  AND token = 'A1gBYyvBU/cF6fAzhKc9zO2K+8a+H66nRUZx5E6/JAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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