SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '323bee4b14259483a28271ce25c67fa2d07998819c07f77bdf73a32fe232a4fe' 
  AND token = 'bDhVKnnBrgbSY4CtQVS0LLxrx6+CLA8n4bgGOofOUVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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