SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba909af324cc67d066099952a12c2a0d1cc5ea1d03467bfe7c65072294204f94' 
  AND token = 'sUnH3uAhZ+lB4xqA2STQI2ZkXQMu4kpvvfpxaJ9wec0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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