SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '366223819329a4585ee27b8011b637690033ac64bc306cf269c110878d364912' 
  AND token = 'MSn+NtvSWVay+GGxOxRY+CwHAseSJOQM0TZMAgO8XUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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