SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88b6b0792448dc5b39e3c7e766e732d77917d3904ce31116132c22ee6ba6ac15' 
  AND token = 'DVgATvuh4hfSvNq3K0jcUGoD+//Ig8Cgxzx2z1wIjBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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