SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac4f6cd66107029613f17bea35af761bfc573e83c878a6eeeca29aec8c2194bc' 
  AND token = 'levEL66Kj7YXdlDZdldPaDtNlH4wU/UUZK5eXeAwWHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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