SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77ab70a8e1787112c38105aeff3fdfd1654fcc15ca3718a4a8c6bffd58a558c4' 
  AND token = 'exBfog+wqOH/s11KlSx8hhfKm7h3u6SzfZXDPV9hz8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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