SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a18c8fdb5bf9cd41762d2dd90ab11933a456445b3e5eadc6304047d3437bd317' 
  AND token = 'wzbwcp6KId0U66yRZhGozXVKPqWTPtPopzKQDWMK8VY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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