SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e6768daabbc6567f9759d41f515a4b9520e1098a2898a7f82a8d6f482d5b8c5' 
  AND token = 'hrF2e1e5zYUAdMVq8GLPDHJxhCXwcj0fDQYsmzAt+Es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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