SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c20b470dc548184eca2fc1f66e597cc8eadc99ff3e396292213aea96d8dbded5' 
  AND token = 'CXazuAlL5ozONcHrzDwrMiho169zKAFJB4xij+Ibwq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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