SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5036915fa5f16cd4bad00a4808905a27c53903649d705f4990f30ada11a78d14' 
  AND token = 'QOflSnOAgrylwx+e/OvpqSq0rOMuHBCcJtORBZfL2lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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