SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e6c3ab49a255a04218258f311c899baef838c0766cbf2907109191168add11c' 
  AND token = 'ICZjVSNOWGuds7LfLj+oqHWm0Nbcc2FyJhwUkbz7JvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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