SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '568244bba0c14ec9584736841c8b88d5b429996cc9ebf854dc7dad18d959d287' 
  AND token = 'bDfWP/50iRZbsmVL19/gOfIlWs40j/thRIMOAiSD+ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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