SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12b49812763b7b6a8c95128a7af47b2b7e548356c5a6c25922a6ae798d201bfa' 
  AND token = 'J+50lrvPm6oQ+R7paf9k2BdI5LCxlqYzjylK5G5G3Ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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