SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c03607a73e876e4a4c547e89c74003a2498d3dc17da83e26fb2e30bd2cc5e202' 
  AND token = 'XdgiLPteNebUoxhwSDkUih8adOjZZZkLoExGxKb9aNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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