SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4a874e2a4ccd34a76ae1a3ebd518cef583ed0aa683653f353927c7b0e2650a09' 
  AND token = 'IG6Zpb154M5EQwq9vQO4UOihVHoTB8oZYJxnQ71sdNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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