SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '827a8a5601717840c03c320b7a052adacd1c39c806e046283583230254b9f939' 
  AND token = '/YY6lgH5yJpq/exAwtJIuxEjgogtUz2TBEjjnRncrgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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