SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dcac8e4b9a7a0996b53935af4be1b931a7a3b79050fc0049813161ff278b3cf' 
  AND token = '2vW9VcqeRiwl8iwqmmWXv/hC5/rs09tWWz+p+0VHyTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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