SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b572c1db286c4beacf1f3fabc6bfddda877c5b60290153a03c0c3c4347ec5b2e' 
  AND token = 'SKZ1Kv4xo3QvYjn6ddThE9mjxIQIwxglss2r/5Z4vsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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