SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e52f92a7ba0d8e64718015350652c99391707e3f8befd85b3face6630f5b667' 
  AND token = 'QGKigbeSEQIrhZ0sHU+2qrYfTmRjuQtZzXVkmC10QkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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