SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9d000d44c10485d9d3982ffb1369673d38e0b16b134b7f814272a32e729d5c1d' 
  AND token = 'qrtQNa0/aFxWo4n5qan18HoXQzhn/9p4L6GQLFnxfpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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