SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '670cf6eb4c1e34c6c58d807d0d2238c3182f67aea857fd56a6f2fcb6a588e266' 
  AND token = 'BL9dIaFQXCWI+QLIpEEoGtIAiDMOaUmIxWb/5Jchywk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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