SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387c98da842866b380f475a3aaff9fbd2c0013ca182c38e297fe1b62dffe4061' 
  AND token = 'G3wKStGF/n9zZV2TVoPCHBQlUjQuRw9/AKTHgMgYT+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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