SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84827b46eda201afe531a16fadce50dfb15d46d71227e1a744bc25dfaf59119' 
  AND token = '3HgWlsqpnxJE1/FpAKZQFN6BYIqc/qxwjFmFIiCi560=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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