SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa23993c6ebe44ac23af144d6893aac698922f487dd5cb02d5b2115e76043b11' 
  AND token = 'j+NNhC2BlK/L6Mq8WjDZ9D9KVNZ6guf5MPiYiIoiDIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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