SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b9e460c17a6a2a1149aeedf6564303382a493ad1dd03469f701d89a6229bbaa' 
  AND token = '0T7tHnz1YTY0M8I6WtFIIuRSe+YGwp88t/4I6H1ZbhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}