SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91a6d4e605a6e9ff8593815ee7207736839fd0409d2fdb5ee6eae37697e3b75d' 
  AND token = 'dofTPgAGLD+LZelvJHS5N5fcwKUw74iG8b3sO3Gp0us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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