SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4b361daeb247fcc48250c3df7f051d4f6e801c7891e573c261dceedb3da81b3' 
  AND token = 'yxGvYa5hUKciJKJSMuCQKI5FXYYuihPibhTjeGPu1XU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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