SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3efc58f63e296c1d1ed192b06d6075fd7c6ac6fe425d7fb6778273f4092aab36' 
  AND token = 'AbWuBWNB3JBwWRZIAGZwvrZG+KAGBLmpkK3WoqfxURk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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