SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a4ea0e0d63c00cbf1765653809ed040fa439d6f53a2f6d51e6a55974392a799' 
  AND token = 'NsjxHJlYPhx/mpG8M7B4kDhEu+xwUVe9jFEj/n35dYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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