SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '901ed2eeb6cf825c15f1a55a97f5f2693e98b3da8bbd880974b7bc28fda57668' 
  AND token = 'UqsLKwwl/08H9SZK1A8ExDazOSV7e+LoNWahk4X39Jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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