SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '16ee70758a3881e8e87f17dfbd946dff970011757290c0549c225adaafecabbb' 
  AND token = 'zUjZutZXP+JcF4j69CHjBO/L1S3Id5bwZKwd4b5OGpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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