SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa8446ecf74958df60d15a623063fb9d8e92949325f469af75371838583bb1af' 
  AND token = 'wPoDzyEY1HEY4LD9dJZg3wHryiNZZHPB+AN8YCjYtWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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