SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c6c2fe3a16348ef91837d8acdace6233c050740ca44865c7d37a349bd4a5c64' 
  AND token = 'AFZwEaqcQtj2WaMKq/jKQ01W/vpsNNnmrG2kX5jLAWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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