SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7619456bc554fdf8ddd95b1adfc4cf6da693094c9cd901c0ff00c85087d36315' 
  AND token = 'PiqKfi9vpVKz6GCeL872fPOucJOEpFkc6oeh9UnxXaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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