SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5166634033b40bc986722aca6828b400a8dd0f3d6b813d95fcf88b089f0559f6' 
  AND token = 'DjEa0yZrvxPl4mwr4EJRWgbsdkBHDDgujVOEPOKadh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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