SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04b164b39df9502f54a6d3bfc34d953d7b92c32f96ec4d2f6fc6a7fce6fc4291' 
  AND token = 'KZhlltE/d1OY3bA+YtvKxDfDZD95AwG3GhzFiBELJic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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