SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7e7b5b436e8c30494aece3e515a37de853a2ab065631aea6363a4eea27702aa' 
  AND token = 'nQJ4WqEpfC9YxCT5LZlKth1eTu/gmP3lTAN7feirD4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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