SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eb0adb82dbb30bc5719ef746c35d85f07fed46b0f7910925c7f5c1c1146a33d' 
  AND token = 'WRSY2HEHAoFSKDELFNqQBUSuhLK/OSeMLjDyZx5rEog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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