SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f96980462eb80eee0cf2866204a32394895544fb93ec45cddac308538ecf5556' 
  AND token = 'v1tYU+iSr7CzfL9HcB4uv0fXaX6CGymON+QEck+K6iI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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