SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40fa696dbbe8a4cc75e54144a13fffd78bcd1b03199b70dcae4c87a393579f40' 
  AND token = 'cT5S8FXdvPyfCzzHULe4LOgHMfw9UM8kTAEPZ1oqBXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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