SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0bbc2beba244271241dbbaec90df9ec2e4a264ec86d779010a7f3e7f85bb7d21' 
  AND token = '66/weca3cAq/cOUAEsoceDxmPjjgicWJ4MvClPSJJsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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