SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b62ec5fe0af31412564f033c80ca0931522487c8ef8e09dd1db551f7a27aad23' 
  AND token = 'KIBITD4gXgxNZqfpSgbg/kam7vvZx8SG9VltmWvyF2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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