SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3e4f6145e22efa364a5ea496ec756e85efbf42d39b89aafe21f587dc88c7ec3' 
  AND token = 'VyimCTBkLfQ52koO+AgnOI3nI+exXN+aQZpq4VIziqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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