SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af1409ebc6b475858758fc73c3aae767ae9dd100b71ec53e8a483e44c919fd96' 
  AND token = '79sn65mwKHhPfLK7GzGO63rfzkJ9uzdZyhjFMxGqPZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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