SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f24ee78163f15b05d149d5caa6a7b3d325daa399ba9d65d62826f24fbd5a8859' 
  AND token = 'U4Rurb3H94Kz0iccgJrPQuTvd6LRDD7UgPVL52+Sa10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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