SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '26dd387063f4cf92cca95de133a343b8c978907be9d8202ab4763516a646966f' 
  AND token = 'Qp6NA5G+cmOibO7vuCl6KLV8tVrBlULAZNDRFfZhYTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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