SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6fe28f03659b506bbea40a7f363159e3f477dab5716f444e3f46ab64e39fd64' 
  AND token = 'TZXPQrVTVmvpvpFaLTHDulYBOkCSKK0ym4Px489FbKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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