SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3ea93b2e240433b260cb5486d2d70f850e0c33ca0f2b1630492eac36afbb710e' 
  AND token = 'dI8A+7xLA3r7h78JqWWC6Now2eSYvH49/U9SHlzfvik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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