SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49824989df8c04174862a3acf98b6392739d4c3e127b5fb7e69d75e560bd2d20' 
  AND token = 'I3qwFEfZqWp7PRYhBJsM0OnNgaqImBMeZifC/vn7+5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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