SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcbf246b0bb91294ed879a43a8b39b3b92075ab46172f4f2437abfc4b2c4008c' 
  AND token = 'YvqbqddgNEWnzKDctoZrqNnYrMhzDdDSZwI+6tOI34o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}