SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9abd0c4fb0ba7906312210f13a5776f75e2e973ce6b048190645a079d8acdc0' 
  AND token = 'C9wqMCqK1AUlKZKjp6J5xhlL93GtZPA8dEvRo7lLGss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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