SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f89a2b3a973b9664ca514bddfe9677863b345d823b82a6fa9cc89ef9e6ef3352' 
  AND token = 'Z64AIi7XNHnnWsiKmOixMq8NXUOhSKneaeXBnduNoHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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