SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a452669037dd93127b52a7f22ea72bb3470faa369d57f26774fd8f011f56a3a' 
  AND token = '5K8/PeqvbN9GzrnjiB9I9u3mlapWwxfnwxxrDWIBODw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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