SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0fdf15c711aad954622e663dbe15aeb1343e9bf97df7750a8486b6aac97b42fb' 
  AND token = 'ol0tqzikj5tqmg0m9ptEVAdf+Z/1vqBO08AgF4Ze7zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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