SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af1a558d95432905b9b59df8b2706a8b03c7993a119f70b284741961a8f81662' 
  AND token = 'Gv6v9iVxE+WOXrBrlcljhMaisXoimO7tthSJ24YnZjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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