SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1946543d77a8314eb22c4e0f0ca51fc604d7ea771dffe1977e217fbdd6a96021' 
  AND token = 'XW84aqLc71jrRJbXtj+BNYMJUtXQlC8QJjwqXTAQo9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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