SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e571c49f105caf8f522a324f979433a3c9da82fbc61317e3df26d74d241b5216' 
  AND token = 'Y5VXyrXSe2AHFUvVm0BB6WJ0JmWwSSWqPWyAG9e4CGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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