SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17589d2910d37435cc34a338be6b31f07c093c17fbe33464a71d57bc98ff12b' 
  AND token = 'gsh9c41NljdNzRHwlUO1F7EcHwM5cynJrD3psYXniDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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