SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ebbaea715fc9937b04284c4c36fe2fd14830ba306f79cae3acbd05a8cd9f263' 
  AND token = 'YMbSm9YONjV3+1dIyyNgIu+QCkuaIYgp18Cl+TzPadg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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