SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b8894dd2ff50da1c20d2550b455e5135e1421ab27a9c859925299d051b5a94' 
  AND token = 'DDKr/IoTmi1JjWpgJUcNJGMBAX4MXsMJNYjPsV61Nto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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