SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a131bbbdf5723b589b968cd4c0aeeafa797281cc113cc1e994a6961d650eafe' 
  AND token = 'lAg65JSFQ9cK+nr6GqAtdDF9oTf4OamtI9QyXvGE0tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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