SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cd07df672c5c5b9b2f29688471590c485cf30a1d82ff8d1e43a6ba91dc6d32ad' 
  AND token = 'zNCxcteZp8TsSKx+FBx3TmuDVW9JmwpqWVB+zG5bQBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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