SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce2fd69fd3ce6c197c4c8ebb0d54eb86208759b4b8bc2870f9aef9b365f7ea35' 
  AND token = 'XG89XXA5CXCqEPPUyUm6gvkuLKFqUz1DHQi59z+fOHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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