SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7793b5fc7f97e44f4496f0688537516e584135e14a5766ccf80eccfdd86e0243' 
  AND token = 'Kaz7WTey3nTEZvWszL+iyS0lqgWbJj2xSvCIGHbksBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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