SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7af68c13741a043d0170324e2b62d3cb8518c08ff309bd1ad1b8605ca625c25c' 
  AND token = 'K+XqiQrO1G1GaoUXOoXjjlE7HjMKyE0sgYzBHhVUMIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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