SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccef7e9eb76396c69d442b8783cda4382fb11973b03f49617c8ede0f58ba1c6c' 
  AND token = 'mLKGQEJh2x+YFJMMPH1jq1iQyUDjKTXSdnNJZdaeFQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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