SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd535ffb28593f877b18a48d7b3e316b64af6078bf4753682629a726b52700559' 
  AND token = 'B/YiuqtgfZcH5A9Y7Qb3sey66XICIetP4dtmqNsjmZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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