SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a5d936435408abf5ec9fd6b763cd4fda1bec6b9684240b949f2bcdb197e945' 
  AND token = '+0QRHAD6/4p86rIkvRiYoOhHhIvXxp1es6hV63TkasY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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