SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ab2f12ae05807a7c9b7912574dab1deab0463ace6464ab910f310027f4d86a5' 
  AND token = 'XuFZeG7P5QuQp4Lj2lSrg5v1i2IFcnCNesGejrfKW+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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