SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d1ec83c0162dec25f0963a90088579d6382fa66f7bc3a624f3db83484491a58' 
  AND token = 'UVewd3TCzpO8zESmPvMIKKMNwvTVWxTf9SZJMKbJKMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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