SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e0e8bd18654f1c043d54f8c19c2741d3b486791437a2bb2a39404418334a5014' 
  AND token = 'z6qMQsjHxsnNA3wrU4GjSafImY4RjxVm78jyYTRZ4Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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