SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '458b727606323008743db0fd5c694354e03307d1f9e24f1cbb14c7babee9c3fb' 
  AND token = 'VE1hrip1TmSKgKV4LiwmJh0Tk+BG/uCqqB9JqAhzj1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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