SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7683549c5f4d749fd283fe3037754e9c31cd00b6e8ae5e08005abad9b352f11c' 
  AND token = 'gqAJJB/elR1hUte5J3upjwZxrlhWK0GzJ9n0nLGfLAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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