SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43684189416b79e7950493b5924fddc58bbab20fdc563f6b97398233cd40de24' 
  AND token = 'ivSuRdja7v1Jx+VvccrweSigiEofVA7eVOUv+KbjkZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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