SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e94332091ea334963693ebf0c42c190d21c7034571f5c272b0f9c3f7d3f4f9e' 
  AND token = 'vyxjC2Ic4G0rtVgDBSTZwCt9RcO6wn7sOIaST8b0V0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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