SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e9515afddf6d394a79db1051c96f6e84b78bf0f68ab36d27b9a0c0d4be5f1cc' 
  AND token = '1cImhOLaWrLkF9g3LlHkJqWzX5ZMrvVy/nHiQ3e6oFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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