SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a435c43930a3af869893fdb05e81667edaf7b3258c3b7b54bda202b54d6f3bf3' 
  AND token = 'JgpOqLotNH8GZLyY6jg6zC+hc08RN+4Qm5JoHZR4uXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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