SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '883ed244dbb6f4a6e8123566c36987c1a5a94c791389fab53178fbc4c802fe38' 
  AND token = 'TBpXY5jOMCRPTdUQftdCJv9gPU9TkfyW82+UPddWk/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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