SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5be90a006d08e7ee78165a97361b30bf0d82e4721935b9a94b734b9c964a5515' 
  AND token = 'sgytJpLf36lTWN02vFSFGgfX1Z6CpDEiD2PIQFLyB8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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