SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f763e9d23b257e79ee211bd1163c9d47ec541032ad8e06e86bc7aa58ac8a635' 
  AND token = 'q3JvSV+mUEBxf1MUhw0YxGhFqrjXQjefWfMDJsG1ag8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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