SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97690a3a337e96e7f142e6528a567fef215dfd743b254124e5e3ce50a353cf1f' 
  AND token = 'RQqKz+OTWwpeEi+hyG4IypNNoYNqWRC2qrsDu8ypwjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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