SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd456aa17baab94caf2142729380988a93e7a0b4fa6954088ac431431b718ff25' 
  AND token = '3lcgJ1bQxd2wWNwiVv/P9s6yO/Hv/ZHrzxBtPZjAyS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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