SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '966cd1dbd7ae330e0ca3454a1426180649ffad131781337ec0c8d6e9cf9be59f' 
  AND token = '1u2lP9O9RYZcK5wOBHDlwbbcotBZ8Ffd7/7L9mrvhb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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