SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2082bfa1f81ef224f4130a642b3f56cfb3ee805865fd5c257275c3c6f802a13f' 
  AND token = 'vn2QELn5gzsqKOMtYQn0aVg5nrBcjeBeZIkfsKWaSf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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