SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35018cc69d5b9309f9bbc1d1df61b6139fe041ff0ef0807df1065fac93e58b4b' 
  AND token = 'e8kC5iQPUPRDgz+VNf0LKVYJiYdnqSZpec8/FzA603I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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