SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab6c7ae01a235dc983d203a393b414ffa81d6534163f282de35182d47c6cd351' 
  AND token = 'i0IbfboqXAlTELLxaDvNwZp0zC+YoLKg6er7XJAjTuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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