SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e44fd7eb630ea5e421a40f0f72b3fd57b721557f265bf356f0658e15198cba6' 
  AND token = 'fHGQEBN1ufREYSDkSaZqWScmpyEnGGZ6Lr33N8OaBQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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