SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d69560b985b6d56e92c5c6f54582d8a4ea580211a09a617d1339641bd9d2b92' 
  AND token = 'EagEJmnVgTxpFFF9dRESebgbsHbDuGxXzYTzvDgW150=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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