SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed661b3018be902c78ba2567afa41fcbca05c3b4f05c5e53fb75df5539e82e2e' 
  AND token = 'CHsVaQtNFpaWjmZ4cReHcJ/sqjP0ERw0MiNkohW16x8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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