SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb9ceb692e91c399547d2e3b8c8f36d3dd5830cba16201532711460f78ecf7b7' 
  AND token = 'N++JgjS2r3OL1sfvJm+Zk0aChqKHA09XhQBnJhGh+fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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