SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b3f87e3dad7e1947bfcf905176d3b929032476dacce14d531b76aaa597f5d88' 
  AND token = 'JPe1IxwHuZnh4GjaM/mksDTuv8mG2OQUUlqwsO68rQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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