SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5c6df90ce6406fd8731d8fac8be4b843fc48bc3cc6b3ee5b917889cace9aaaa3' 
  AND token = '9Dxudu4zie2c72V5Ph8maYtsKdvdXCw6QhFhjz+o9+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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