SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78dca6ad8c7b3f780ed45b95935b284133177373af22fca43548bee6dc397798' 
  AND token = 'n/2+ijjXkQltNj08gPR6PUw5WPY4S+JKu2cuK+/4zLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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