SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15b62966b386712d90ed3e5ef9df1de6088bbb09b01ea8f801373ad1a15942f5' 
  AND token = 'rfckc8bLBkoT83Tp6fs+TqWyhAlIze9IYmQBXXRcs80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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