SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468b89daf458b54cfdb81d736dea1da3208507766b9af99e2e3e7bcdd8acd72f' 
  AND token = 'ZIHvOGtg7EiJOCvGwX6KEB8ZGXUV28brAUIt+Y3h+Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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