SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5da97993da2c988a889b5daa73eb75c491f0327cf39ff0d7de018eabd9b10872' 
  AND token = 'UpjIpLXLPc+lKo6QQXBaxL9ZWJzZYebsvI0aM6jFcRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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