SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b07b658465514fce4ea789ac2740f350b1e659582e23f6ad33997f49445bda94' 
  AND token = 'TbQhzdLOgh9R1E347BV7dbZsqcbmsGU+qHbqKNnEiNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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