SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11db322a5d3e741eacf74521fecaf87fed36c3dd09b10e2d337ec3179b6248c4' 
  AND token = 'afUcTxowuKPsJY4IIfIh7tiAFRsS8XsQl2+JAOUSGLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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