SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1fa380c9652304bc4d45553268975eebf7f9231df17ffd05c93b918322f7535' 
  AND token = 'htrZEv9U1S3nHo/fIElZ+jockPvkLOnHR4JIXd4J8Cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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