SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0494daa87c71233294815ec591410f12cd13397b75da67acd52329aa3019ef8d' 
  AND token = 'COBncP+txeL9uaO8D8406zSWd+d4VvvxSGbwrAUj4Zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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