SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f62fb19d3f6af92096182b9afb477548be8b985362069aafde9b07bb21daf271' 
  AND token = 'eevfp43/doy+lS6hUhjsNaQg1Ap2iZ9DYiKLuzqVvXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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