SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca8cf7c94fb6e00ce4df515d7071a750ae3ccc8cc6d0970c3ef3cd3356430cd4' 
  AND token = 'VZwK33JR2kY0+wYCGQ61U+GGRqP9811FrgITIC1gCl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}