SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '334a7f3b727d14ce42c3d9d3fd446a609e492aae9688ffadaaf158a4502a39e0' 
  AND token = 'Cl3TRoSv1DKkQ6aTVc4cenRvZydD49GnjKVSrKLWxuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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