SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c3f70cc39060f66cbfb9e3d45eac9ee10e8c78a0e40ab7b95db0a50b300702d' 
  AND token = 'R2J9r2c9jdehvMo2TKrLGozdoKvqPLGt6KDzmqdkCto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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