SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0df74440dedf205460d6347f87ce58a847e513f6ef933aa23197a84994328d14' 
  AND token = 'qjyuYy66CqgmfjHUeMKA+aNAwualTDFz+FB/LIdaBFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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