SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5656166ba3f25eed1cd7cbbfea2684af8e2b81fda00218c0ad77227fbd5054c1' 
  AND token = 'LRqfg3EJA9i9KrHVgOvOmZJ0dt7ScZxNgelOI6gfoVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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