SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13516b026b16f73ef1affdbf38ad074fc67da98668491bdc07184283e2c50bc7' 
  AND token = 'mo0qrQATb+BBNxUB8k3wSSDuyBdMcCv9TIblyY85LfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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