SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f188ea593872ada88b6181a55952308525efb19766e1ae41019f2cb7539d9f53' 
  AND token = 'fbdyvyv4D03ZKbF6lBzLSg5HFFxsntJPkHnOqUTScnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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