SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b86dbbedc99ed8503c4ca26f580dd999659a8f8821c6942c998294da368de4ff' 
  AND token = 'XyHFIyfq6mTvq3kMdwhC8Yqia72H2nHcWYp1an+E9i8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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