SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b3730e7c91b7d9e03ed411f78d74ef4103ad1b73cb90f3c8817b842c25bd7bb' 
  AND token = 'UZD5WkX22dPIOZNAKJ76jQJkVWdrwg7QYUgc8gt7flE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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