SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae5cfe557f15bd7c32f5fdbc6d9527ee9a29f7ed87a8ee91bfd2b0344775c552' 
  AND token = '6hSiuDZipho7qTneBApGgE+pLiEyMpSpt6xknGYnVsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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