SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '153ce2fe5384c9a37cecb180377ece5c9464c86decfb71b6c4eea050a0782b12' 
  AND token = 'ZGo9dtUXlxzrOx7mJDQC6of6GnhPRG3yg36PyUeASUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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