SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '963bd79bb25ebcc9da77cc700aeb66bf0514ba736b7bc5f58a38047d806f6795' 
  AND token = 'NWiUjYMe0HoFVpqHUMSz4V7E0ANlCd8K2kB+F6WSEz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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