SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08adc35ebcc83a2ebf0ae76268d5d7ffb073f8786df253f1a0614011e22f93ce' 
  AND token = 'cmR7jgPNEK6NzbTXO09qzNfvjwIhuynoMY60lbQvtcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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