SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '350d8423b47eedae3508e0ad4ebff03af8f46aed4c3d388c44ee2347fe80d5ff' 
  AND token = 'YDgQGePnIkg3PRjYUJO77GypGHtl1Y4UZzrybN1VaU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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