SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24f68435f3382f1126c4c0ae282345e5ee8d1e47f26eaffd72a941c531592baa' 
  AND token = 'mKSrURkWUOT7592VV4ZpGNJ3RmKcSLTl06jcpa1UnxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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