SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '46251fa47dd6b3ea2d1f1f4cfa4659a7563cc4e8976ba2e53d9cf6229e24ef70' 
  AND token = 'U9VatuRSCgVPL7ngZeYhT2IBAvwmmTjktH8lcBSsUKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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