SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5506599d37fc9a2c177b7b7fe58d556a6a62e31c5c6528100421a5ddd24f8900' 
  AND token = 'uZfWXgQjs//YQCJ+qX7YtidclMqkZXYU3PH6PE4lBRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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