SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7966a04808a5af8df8ae4ac913547a0adef7ce3ea8e399f25492b467e234e78c' 
  AND token = 'B9YwhrZ9xUWnGcIYkzmWMCz+V2BnXlfpyCf21rP6jqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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