SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2094033d3d55b536917161f9172d2f40de1be1bad51248858358f5be164c83de' 
  AND token = '1qlNi2SPrBzotVxTbe3MfNDE1OjIk3bIlzQ3AEZMZq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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