SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '391b9868c16ef87475d9cf8c2d7fe1e74a2b587e8dd221455d42b0ac2807b047' 
  AND token = 'BUQ2I7quq+odLvg1jef58oSDNdUUpxJZ6aVj3VAfgnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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