SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d4bf678aa64b73438e487a145be2b74a4c133eed0020795e2d6145c9759d4fd' 
  AND token = 'UKrzSA+/KQX6CLKd2Kv+XBZVIBte6LYtO5ok7KdbMvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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